Variable electrical resistance



Feb. 17, 1931'; H. N. HITE VARIABLE ELECTRICAL nn'sxsmws Filed Sept. 6. 1927 as A? mvenfb/ Mm/d 44 M76 Patented Feb. 17, 1931 UNITED STATES PATENT OFFECE HAROLD NESBIT HITE, OF HAYWOOD, ILLINOIS, iSSIGNOE T WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK VARIABLE ELECTRICAL BESIETAINGE Application filed September 8, 1927. Serial Hoe 21?,643.

and thus in some cases necessitating the rewinding or replacement of the coil or at least rotating the coil in order to provide for a new line of contact.

The object of the present invention is the provision of a simple and efficient means for varying the amount of efiective resistance of a rheostat without unduly wearing the resistance element of the rheostat.

In accordance with the general features of the invention, one embodiment thereof com-- prises a cylindrical coil of wire and a resilient wire disposed substantially parallel and extendin longitudinally to the axis of and close to t e periphery of the cylinder which makes contact with the cylindrical coil at a oint governed by a movable element carry ing a resiliently mounted rotatable member pressing the wire against the coil.

Other features and advanta es of the invention will become apparent in the following description, reference being had to the accompanying drawing, wherein Fig. 1 is a side elevation of a variable resistance embodying the features of the invention Fi 2 is an enlarged side view of the slidin element shown partly in section ;and

ig. 3'is an enlarged sectional view of the sliding element taken on line 3-3 of Fig. 2.

Referring now to the drawing generally,

and more particularly to Fig. 1 thereof, the numeral 5 indicates a base of any suitable type and material on which are mounted hard rubber members 6 and 7, which support the cylindrical resistance coil 8 comosed of any suitable resistance wire and aving a terminal wire 9 connected to the binding post 10. Above the resistance coil 8 extends a substantially parallel conductor so 12, preferably of material of a resilientand long wearing quality, specifically a phosphor bronze 5 ring wire, mounted in the members 6 an 7 through holes drilled therein and held in place by metal discs 13 and 14 brazed thereto and maintenance in suitable tension by a tension spring 15 contained in a countersunk aperture in themember 7 and attached to one end of the conductor 12. At point 17 a screw 18 contacts with a wire 12, affording an electrical circuit from the wire 22 to a conductor 19 which leads to the hind ing post 20. Binding posts 16 and 20 form the two exterior connections the variable resistance. A bar 22 eztencs parallel to the wire 12 and the axis of coil. 8 between bars 6 and 7, and is secure thereto by screws 18 and 23.

On the bar 22 is slidahly naov able device 24 for making a movable contact between the wire 12 and the coil 8, through an arrangement which will now he explained. In the movable device 2% which is com of a non-conductive material. such as rubber, is an aperture 25 surrounding the he 22. A spring 27, preferably composed c steel, causes a resiliently controlled centers of the movable device 2% with the her 22, is the pressure means that holds the epr wire 12 in contact with the coil 8. The 27 is held in place by and is removable 'n a pin 28 mounted on a metal member 29 w'iich is secured in a groove 30 cit-the hard rubber device 24 and which has slots 32- 32 in which are placed journals 3&- and S5 of a roller 33. Roller 33 has a groove p tially surround ing and engaging the In the operation of tee apparatus to vary the efi'ective resistance which may be included in any suitable circuit through the binding posts 10 and 20, movable member 24 is moved along bar 24: thus rotating the roller 83 which holds the wire 12 in continuous varyingcontact with the resistance coil 5%. Wlnle men-- her 24 is moved to a position to give a desired effective resistance, spring 27 afiords the necessary pressure for causing continuous varying contact between spring 2 re 12 which is maintained in tension and resistance coil 8, as well as efiecting a sliding contact of device 24 with the bar 22.

It is obvious that after the movable device is repeatedly moved back and forth there will be little wear in the members forming the electrical circuit. l here is very little friction exerted upon the coil from the contact.- ing element, and practice shows that the slicetive life of the coil is greately prolonged as compared with a urely sliding contact. lhe wear that arises due to the movable roller is confined almost entirely to the contacting element; which when worn can be relatively easily and economically replaced.

Although one specific embodiment of the invention has been herein illustrated and dematinee ance element, a conducting element disposed substantially parallel to and extending com pletely along the resistance element and contacting therewith at a single point, a tension spring attached to one end of the conducting element for maintaining it in tension, and means for shifting the single point of contact to vary the resistance.

In witness whereof, I hereunto subscribe my name this 25th day of Au ust, A. D. 1927.

HAROLD NE BIT HITE.

scribed, it is to be understood that the novel I features of the invention are capable of various applications within the scope of the appended claims.

What is claimed is:

1. In a variable resistance device, a resistance coil,-a conducting element, a spring for holding the conducting element in tension, a bar, a movable device provided with a slot slidably and resiliently mounted on the bar, and a roller journaled in the slot in the movable device and effecting a movable contact of the conducting element with the resistance coil.

2, in a variable resistance device, resistance element, a conducting element disposed substantially parallel to and extending completely along the resistance element and con tacting therewith at a single point, resilient means attached to one end of the conductin element for maintaining it in tension, and

- means movable longitudinally of the conducting element for shifting the single point or contact to vary the resistance,

3. In a variable resistance device, a cylindrical resistance coil, a bar mounted adjacent thereto and held in fixed relationship therewith, a conducting means disposed substan'- tially parallel to the coil and the bar and em tending completely along the coil, resilient means for suspending the conducting means in tension, and a. device cooperating with the bar for progressively forcing successive portions of the conducting means into contact with the coil to vary the edective resistance.

4. In a variable resistance device, a cylin= drical resistance coil, a bar mounted parallel and adjacent thereto, an electrical conductor suspended between the bar and the coil and disposed parallel thereto, a spring for holding the conductor in tension, a device mounted on the ,bar for movement therealong, a roller housed within the movable device for pro gressively forcing successive portions of the conductor into contact with the coil as the device is moved in order to vary the resistance, a metal member attached to the movable device for housing the roller, and a resilient member secured to the movable device and pressing against the bar.

5. In a variable resistance device, a resistllll 

